Health Library

Macular degeneration

Age-related macular degeneration (AMD) is a chronic eye disease that affects more than 10 million Americans. It is the leading cause of vision loss in people over 60 in the United States, and the number of people with AMD rises as they get older.

Macular degeneration affects tissue in the part of your retina that is responsible for central vision, called the macula. It causes blurred vision or a blind spot in the center of your vision, and can interfere with reading, driving, and other daily activities. You may first notice symptoms when you need more light to see up close.

There are two forms of AMD. Dry AMD affects about 85% of those with the disease and causes gradual loss of central vision, sometimes starting in one eye. Wet AMD, which accounts for 90% of all severe vision loss from the disease, often involves a sudden loss of central vision. Most people with the wet form of AMD previously had the dry form.

Signs and Symptoms

Dry AMD

Symptoms of dry AMD include:

Needing more light when doing close-up work

Blurring of print when trying to read

Colors appear less bright

Haziness of vision

Blurred spot in the central field of vision, which may get larger and darker

Wet AMD

Symptoms of wet AMD include:

Straight lines that appear wavy

Objects appearing further away or smaller than usual

Loss of central vision

Sudden blind spot

What Causes It?

The macula, a part of your eye's retina, is made of cells, called rods and cones, which are sensitive to light and are needed for central vision. Underneath the macula is a layer of blood vessels called the choroids, which provides blood to the macula. A layer of tissue on the retina called the retinal pigment epithelium (RPE) keeps the macula healthy by transporting nutrients from the blood vessels to the macula and moving waste products from the macula to the blood vessels.

As you get older, the RPE can thin and not move nutrients and waste back and forth as efficiently. Waste builds up in the macula, and cells in the macula become damaged from lack of blood, affecting your vision.

With dry AMD, RPE cells lose their color and do not get rid of waste products from the rods and cones. As waste builds up, the rods and cones deteriorate.

With wet AMD, blood vessels grow underneath the macula and leak fluid or blood. Researchers do not know exactly what causes the new blood vessels to grow, although they think that it may be the breakdown in waste removal. That could explain why people with the wet form almost always start out with the dry form. The new blood vessels interfere with getting nutrients to the macula, and the rods and cones start to break down.

Who is Most At Risk?

People with the following conditions or characteristics are at risk for developing AMD:

Age, macular degeneration is the leading cause of severe vision loss in people over 60.

Gender, women are more likely to develop it than men.

Cigarette smoking

Family history of macular degeneration

Heart disease

High cholesterol

Light eye color

Long-term exposure to sunlight

Low levels of antioxidants in your blood

Carrying weight around your waist (belly fat)

Use of antacids, using anatacids regularly has been linked with developing AMD

What to Expect at Your Provider's Office

Your eye doctor can screen you for AMD as you get older. However, if you have any changes in your central vision, or in your ability to see colors, you should see your doctor right away. Your doctor may use several methods to test you for AMD including:

A vision field test.

Testing with an Amsler grid, which involves covering one eye and staring at a black dot in the center of a checkerboard-like grid. If the straight lines in the pattern look wavy, or some of the lines seem to be missing, these may be signs of macular degeneration.

Fluorescein angiography, where a special dye is injected into a vein in your arm and pictures are taken as the dye passes through the blood vessels in the retina.

Optical coherence tomography (OCT), an imaging test that can look for areas where the retina may be thin or where there may be fluid under the retina.

Treatment Options

There is no known cure for AMD, however, there are things that can help slow vision loss. Certain procedures and medications may stop the wet form of the disease from getting worse. Adding antioxidants to your diet may help prevent the wet and dry forms of AMD and slow their progression.

Prevention

The dry form of AMD can progress to the wet form. If you have dry AMD, you will test your eyes daily at home using an Amsler grid. Let your doctor know immediately if there is any change in your vision.

Wear sunglasses, hats, and visors when exposed to the sun.

Drug Therapies

For wet AMD, a type of medication called antivascular endothelial growth factor (anti-VEGF) can be injected into your eye to stop new blood vessels from growing. Two such drugs are approved to treat AMD:

Pegaptanib (Macugen)

Ranibizumab (Lucentis)

Surgical and Other Procedures

Surgical and other procedures may help some cases of wet macular degeneration.

Photocoagulation (laser surgery). In photocoagulation, doctors use a laser to seal off blood vessels that have grown under the macula. Whether this procedure is used depends on:

Where the blood vessels are located

How much fluid or blood has leaked out

How healthy the macula is

Photodynamic therapy is often used to seal off blood vessels that are under the center of the macula. Using photocoagulation on that location would result in permanent central vision loss. With photodynamic therapy, the doctor gives you a drug that stays in the blood vessels under the macula. When a light is shined in your eye, the drug closes them off without damaging the rest of the macula. Photodynamic therapy slows vision loss but does not stop it.

Complementary and Alternative Therapies

Supplements are a valuable treatment for dry AMD. They may also help prevent both wet and dry types. However, you should not try to self treat vision problems. See your doctor first for a diagnosis and treatment plan.

Nutrition

To treat AMD

AREDS formula (vitamin C, vitamin E, beta-carotene, and zinc, plus copper). The Age-Related Eye Disease Study (AREDS) found that a combination of antioxidant vitamins plus zinc helped slow the progression of intermediate macular degeneration to an advanced stage. Because the advanced stage is when most vision loss happens, the supplement can help stave off vision loss.

The National Eye Institute recommends that people with intermediate AMD in one or both eyes or with advanced AMD (wet or dry) in one eye but not the other take this formulation each day. However, this combination of nutrients did not help prevent AMD, nor did it slow progression of the disease in those with early AMD. The doses of nutrients are:

Vitamin C (500 mg per day)

Vitamin E (400 IU per day)

Beta-carotene (15 mg per day, or 25,000 IU of vitamin A)

Zinc (80 mg per day)

Copper (2 mg per day, to prevent copper deficiency that can occur when taking extra zinc)

Ocuvite PreserVision is formulated to contain the proper amounts of these nutrients. People who already take a multivitamin should let their doctor know before taking this formulation. Zinc can be harmful at a high dose, like the 80 mg used in this formulation, so be sure to take this combination only under your doctor's supervision. Zinc can cause copper deficiency, so a small amount of copper is added to the nutrients.

In the study, 7.5% of people who took zinc had problems including:

Urinary tract infections

Enlarged prostate

Kidney stones

Compared to 5% of the people in the study who did not receive zinc.

Lutein and zeaxanthin. High levels of these two antioxidants that give plants orange, red, or yellow color may help protect against AMD, either by acting as antioxidants or by protecting the macula from damage from light. One study found that people with AMD who took lutein alone, or in combination with other antioxidants, had less vision loss, while those who took a placebo had no change. However, another study failed to find any benefit from lutein. Egg yolks, spinach, and corn have high concentrations of lutein and zeaxanthin.

Help reduce risk of AMD

Leafy greens. People who eat dark, leafy greens, such as spinach, kale, collard greens, and watercress tend to have a lower risk of AMD.

One study found that taking vitamins B6, B12, and folic acid reduced the risk of AMD in women over 40 with a history of, or at risk for, heart disease. The doses used were:

Vitamin B6 (50 mg daily)

Vitamin B12 (1,000 mcg per day)

Folic acid (2,500 mcg per day)

Folic acid can mask a vitamin B12 deficiency. Talk to your doctor before taking these vitamins at these doses.

Omega-3 fatty acids (fish oil). In a study of more than 3,000 people over the age of 49, those who ate more fish were less likely to have AMD than those who ate fewer fish. Other studies show that eating fatty fish at least once a week cuts the risk of AMD in half. Another larger study found that consuming docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), two types of omega-3 fatty acids found in fish, 4 or more times per week may reduce the risk of developing AMD. However, this same study suggests that alpha-linolenic acid (another type of omega-3 fatty acid) may actually increase the risk of AMD. It is safe to eat more fish, although you may want to eat fish with lower levels of mercury.

Women who are pregnant or breastfeeding are advised to eat no more than 12 ounces a week of a variety of fish and shellfish that are lower in mercury. Talk to your doctor before taking fish oil supplements if you are at risk for AMD. Fish oil may increase your risk of bleeding, especially if you already take bloodthinners, such as warfarin (Coumadin) or aspirin.

Herbs

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care practitioner.

Ginkgo (Ginkgo biloba). 160 to 240 mg per day. Ginkgo contains flavonoids, which researchers think may also help AMD. Two studies showed that people with AMD who took ginkgo were able to slow their vision loss. Ginkgo can increase the risk of bleeding, so people who take bloodthinners, such as warfarin (Coumadin), clopidogrel (Plavix), aspirin, or any other medication that decreases clotting, should not take ginkgo without talking to their doctor.

Bilberry (Vaccinium myrtillus), 120 to 240 mg, 2 times per day, and grape seed (Vitis vinifera), 50 to 150 mg per day). Are also high in flavonoids, so researchers think that they may help prevent and treat AMD. However, so far no studies have looked at using bilberry or grape seed to treat AMD. Bilberry and grape seed may increase the risk of bleeding, so people who take blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), aspirin, or any other medication that decreases clotting, should not take either bilberry or grape seed without talking to their doctor. People with low blood pressure, heart disease, diabetes, or blood clots should not take bilberry without first talking to their doctor. DO NOT take bilberry if you are pregnant or breastfeeding.

Milk thistle. 150mg, 2 to 3 times per day. Silymarin, from milk thistle, is a major supporter of liver function. The liver is a key organ for maintenance of eye health because the fat soluble vitamins and the B vitamins are stored there. There is some concern that milk thistle compounds have estrogen-like effects in the body. If you have hormone-sensitive issues, you should discuss the risks and benefits with your physician.The same holds true for people taking any prescription medication since milk thistle exerts its influence via the liver and that is where the majority of medications are metabolized. If you have an allergy to ragweed, you may also react to milk thistle. Speak to your doctor.

Prognosis/Possible Complications

Severe AMD can cause legal blindness. Low vision aids may help if you have partial blindness. Sometimes blood vessels build up underneath the retina, causing the retina to become detached or scarred. If this happens, the chances of preserving your central vision are poor. This condition, called subretinal neovascularization, happens in about 20% of cases of AMD. It often comes back even after laser treatment.

Following Up

Your eye doctor will see you regularly to monitor your vision and eye health.